what is the study of genetics?
it is the study of heredity;it is also the study of what genes are and how the genes carry information.
what is a gene?
a gene is a segment of DNA that codes for a functional product, usually a protein.
what does it mean that the two strands of DNA are complementary?
because Adenine always pairs with thymine and cytosine always pairs with guanine.
what is a genotype?
the genetic makeup of an organism.
what is a phenotype?
the actual, expressed properties, such as an organism's ability to perform a particular chemical reaction. it is the manifestation of the genotype.
How are the carbon and phosphate of DNA attached to each other?
the phosphate group attaches to the 5' carbon of its nucleotide and to the 3' carbon of the next nucleotide
to what carbon is the nitrogenous base attached? and OH?
it attaches to the 1' carbon and an OH is attached to the 3' end of the DNA strand.
what is a 5' end of the DNA strand?
it is when the end has a phosphate group attached to the 5' carbon.
why are the DNA strands anti parallel?
because one strand has the chemical sense of direction 5' to 3' and the other strand has the chemical sense of direction 3' to 5'.
Explain the steps in DNA replication. 9 steps...
say it memorized.
what are the functions of DNA polymerase
it joins the nucleotides together to form a new strand at a 3' end.
why is one new DNA strand made continuously and the other one is made discontinuously?
since the DNA strands are anti-parallel the leading strand is synthesized continuously in the 5' to 3' direction from a template parental strand running 3' to 5' while there is a lagging strand that is synthesized discontinuously in the 3' to 5' direction from a template strand going in 5' to 3' direction.
why do the new DNA strands have a RNA primer
because the DNA polymerase cannot add to nothing, it can only join the nucleotides together at a 3' end.
what does DNA ligase do?
it joins the discontinuous fragments together.
what is the replication fork?
it is the point at which replication is occurring.
what is semi-conservative replication?
because each double-stranded DNA molecule contains one original strand and one new strand.
what is transcription?
it is the synthesis of a complementary strand of RNA from a DNA template.
what is the sense DNA strand?
the other strand that does not serve as a template for RNA synthesis.
what is the antisense strand?
it is the only 1 strand of the 2 DNA strands that serves as a template for RNA synthesis.
what is the promoter site?
it is the region on the DNA where RNA polymerase initially binds and where transcription begins.
what is the terminator site?
it is the region of DNA that signals the end point for transcription.
Explain the how transcription occurs.
know it memorized
what is the function of DNA-dependent-RNA-polymerase?
it joins the RNA nucleotides together to form the mRNA strand.
what is the function of mRNA?
carries information from the DNA to the ribosomes specifying the sequence of amino acids forming the protein.
what is the function of rRNA?
forms ribosomes which are the site where the amino acids are joined together by peptide bonds to form a protein.
what are the names of the 2 binding sites on the 60s subunit and what binds to these sites?
one site is called amino acyl site "A" and the other site is called peptidyl site "P" these are the binding sites for tRNA.
what does the peptidyl transferase do?
it is an enzyme in the 60s subunit used for the formation of the peptide bonds joining the amino acids together.
what binds to the 40s subunit?
it binds the mRNA molecule to the ribosomes.
what is the function of tRNA?
it picks up the amino acids from the cytoplasm and transports these amino acids to the ribosomes so that they can be assembled into a protein.
what does the amino acyl synthetase do?
it attaches an amino acid at one end of thee tRNA molecule.
what is the anticodon?
a 3 nucleotide sequence found at the other end of the tRNA molecule which codes for one amino acid. it is complementary to the codon on the mRNA.
what is translation?
is the process in which the nucleotide base sequence of mRNA dictates the amino acid sequence of a protein, the synthesis of protein synthesis.
what is the genetic code?
the sequence of 3 nucleotides on mRNA which code for one amino acid
what is the codon?
same as genetic code. it is identical to the genetic code on the antisense DNA strand.
what is a sense codon?
codes for one amino acid
what is a nonsense codon?
does not code for amino acids like the stop codons.
where does translation occur?
occurs on the ribosomes of a cell.
if a protein is 10 amino acids long, how many nucleotides make up the gene? how many nucleotides make up the mRNA strand?
3 times 10 equals 30 nucleoitdes.mRNA would have 36 nucleotides
what is post transitional processing and why does it occur?
once the polypeptide has been made by the ribosome, it undergoes some modification. the amino acid meth, coded by the start codon is removed by enzymatic action also the stop codon at the end.
explain the translation.
say it memorized.
what determines which amino acid the tRNA picks up in the cytoplasm?
mRNA strand contains the information from the gene to synthesize one protein. anticodon which is the sequence of 3 nucleotides on the tRNA which codes for one amino acid. anticodon and the codon are complementary
what enzyme cuts out the RNA primers on the leading and lagging strand during DNA replication?
the exonuclease
what determines which tRNA binds to the amino acyl site on the ribosome?
mRNA
what does the enzyme helicase do?
it breaks down the hydrogen bonds between the the DNA nucleotides.
what does the enzyme primase do?
it synthesizes the RNA primer.